Feature

This content was provided by Bernardo Patti, and is maintained in a database by the ISS Program Science Office.

Brief Summary

The Columbus External Payload Facility (Columbus-EPF) provides four powered external attachment sites for scientific payloads or facilities. The first NASA investigation was a testbed for materials exposure.

The Columbus External Payload Facility (Columbus-EPF) provides four attachment sites for payloads and payload facilities: one nadir site (platform faces Earth), one zenith site (platform faces up), and two starboard sites (platforms face to the right of Columbus as viewed along its line of flight). Each payload may have a mass of up to 290 kg, including the mass of the EXpedite the PRocessing of Experiments to Space Station (EXPRESS) Pallet Adapter (ExPA) and the active Flight Releaseable Attachment Mechanism (FRAM).

Power capability of 1.25 kW is provided by two 120-Vdc redundant power feeds at each attachment site.

Data capabilities at each attachment site include a low-rate 1553-B data line for status data, such as caution and warning and failure detection data. The attachment sites also provide a medium-rate Ethernet data line with rates of up to 1.55 Mbps (megabits per second) for the transfer of commands, ancillary data, and files. The high-rate data line interfaces with the video data processing unit and transmits up to 32.426 Mbps in increments of 32 kbps (kilobits per second).

The Columbus External Payload Facility (Columbus-EPF) consists of two identical L-shaped consoles attached to the starboard cone of Columbus in the zenith (top) and nadir (bottom) positions, each supporting two platforms for external payloads or payload facilities. Four external payloads (payload facilities) can be operated at the same time.

In addition to structural support, Columbus can supply power and data (command) to the Columbus-EPF payloads and can poll the payloads for housekeeping (health and status) and user data.

The power and data interfaces available to the Columbus-EPF payloads are directly connected to the Columbus internal distribution systems. Columbus-EPF payloads and payload facilities are controlled and commanded via Columbus using the same data links and ground segment infrastructure used for internal payloads. Each payload has a facility-responsible center that can transmit commands and receive telemetry via the Columbus Control Centre.

Columbus provides a maximum of 1.25 kW per Columbus-EPF location. Each Columbus-EPF location is connected to two 120-Vdc power feeders, each of which has a maximum allocation of 1.25 kW. Switching between the power feeders is done via the payload power switch box in Columbus and requires the power feeders to be powered down.

The maximum on-orbit mass of an external Columbus-EPF payload, including the adapter plate, is 290 kg. The dimensions of a payload should not exceed 864 x 1168 x 1245 mm without the adapter plate.

The first Columbus-EPF payload facilities were the European Technology Exposure Facility (EuTEF) and Sun Monitoring on the External Payload Facility of Columbus (Solar), which were installed during the STS-122/1E mission during an extravehicular activity (EVA) by crewmembers. Atomic Clock Ensemble in Space (ACES) and Export will be delivered to the International Space Station at a later, undetermined date. The Columbus External Payload Facility (Columbus-EPF) was transported to the International Space Station (ISS) with the Columbus module on STS-122/1E in February 2008. Columbus-EPF payloads and payload facilities are transported to and from orbit using a carrier supplied by the ISS Program. The payloads and payload facilities are maneuvered by the robotic manipulators of the ISS to their final operational locations on the Columbus-EPF. Each payload or payload facility has an open view to ram and to starboard, as well as one to either zenith or nadir. The view in the wake direction is reduced by ISS structures. At the end of its operational phase, a payload is transported to the carrier by robotic means and returned to ground for postmission inspection and analysis and, possibly, refurbishment.
Operations

Facility Operations

The Columbus External Payload Facility (Columbus-EPF) was transported to the International Space Station (ISS) with the Columbus module on STS-122/1E in February 2008. Columbus-EPF payloads and payload facilities are transported to and from orbit using a carrier supplied by the ISS Program. The payloads and payload facilities are maneuvered by the robotic manipulators of the ISS to their final operational locations on the Columbus-EPF. Each payload or payload facility has an open view to ram and to starboard, as well as one to either zenith or nadir. The view in the wake direction is reduced by ISS structures. At the end of its operational phase, a payload is transported to the carrier by robotic means and returned to ground for postmission inspection and analysis and, possibly, refurbishment.